1. Field of the Invention
The invention relates to a sealing ring combination, in particular for sealing a cylinder passage of a reciprocating piston rod of a reciprocating compressor, including two axially abutting individual rings arranged in a shared casing recess at the passage of a component to be sealed, which each are formed of several ring segments pressed against the component to be sealed by a common peripheral spring, and wherein the cover ring facing the side to be sealed is radially divided and relieved from pressure by inlet-side radial grooves, and the actual sealing ring is divided by essentially tangential sections.
2. The Prior Art
Such sealing ring combinations or sealing ring pairs are used as high-performance pressure seal, e.g., for the mentioned piston rod at the passage through the cylinder floor of a reciprocating compressor. In one such arrangement that has become known as the xe2x80x9cBT ringxe2x80x9d, the first ring facing the component to be sealed is also called the cover ring, radially divided into three sections, wherein the first segments are held together by a superposed peripheral spring, and hence the ring as a whole is kept in contact with the piston rod. Radial grooves on the inlet side allow the inlet pressure in the entire peripheral space to act outside the two rings, so that the second, actual sealing ring, which is divided into three essentially tangential sections, is still exposed to a sealing pressure from outside, and pressed against the component to be sealed. Due to its radial division, the cover ring on the inlet side cannot become significantly further worn by the reciprocating component after an initial run-in phase and closing of the dividing gap. However, the sealing ring continues to be pressed directly against the component to be sealed by the inlet pressure and applied peripheral spring even after run-in due to the tangential division, and hence becomes further worn, which also results in a significant temperature load owing to the frictional heat.
The object of the present invention is to provide an improved sealing ring combination of the kind mentioned at the outset or discussed as prior art in such a way as to avoid the cited disadvantages to known device of this kind, and in particular to provide an improved long-term sealing effect at a reduced heat load.
According to the present invention, this object is achieved in a device of the type mentioned at the outset by having the cover ring exhibit a circumferential carrying shoulder on the side facing the sealing ring, on which sits the sealing ring with the circumferential peripheral surface of a twist-out section facing the cover ring, and by largely relieving the pressure on the cover ring by means of an inner peripheral groove that is provided on the side of the carrying shoulder and in contact with the delivery side. Due to the carrying shoulder on the cover ring or the interaction of the latter with the circumferential peripheral surface of the twist-out section of the sealing ring, the latter can only wear to a limited or controlled extent during the run-in phase on its inside periphery closing on the component to be sealed until the sealing ring is carried by this carrying shoulder. This gives rise to a very effective sealing labyrinth with an annular gap that is somewhat enlarged over the course of time against the component to be sealed due to the lack of applied pressure, which also blends the pressure reduction over at least several such combinations arranged in one packing in an additionally advantageous manner. Given the extensive pressure relief of the cover ring on the inlet side, the latter is no longer additionally pressed against the component to be sealed by the inlet pressure to be sealed, which reduces wear or a corresponding heat build-up.
Since the sealing ring is carried in the described manner by the circumferential carrying shoulder on the cover ring, another preferred configuration of the invention can provide that the width of the inside periphery of the sealing ring sealing on the component to be sealed be smaller, preferably by half, than the width of the cover ring. This makes it possible to further reduce the arising frictional heat, which makes such sealing ring combinations outstanding for use in sealing packings without a separate, active cooling.
In another preferred configuration of the invention, the inside periphery of the cover ring can exhibit axial, groove-like depressions from the delivery side to the inside peripheral groove, which ensure the pressure relief of the cover ring described at the outset even in the run-in state in a simple way.
The invention will now be described in greater detail by reference to the embodiments depicted in part diagrammatically in the drawings.